Methods of forming non-volatile memory devices including dummy word lines

ABSTRACT

A non-volatile memory device may include a semiconductor substrate including an active region at a surface thereof, a first memory cell string on the active region, and a second memory cell string on the active region. The first memory cell string may include a first plurality of word lines crossing the active region between a first ground select line and a first string select line, and about a same first spacing may be provided between adjacent ones of the first plurality of word lines. The second memory cell string may include a second plurality of word lines crossing the active region between a second ground select line and a second string select line, and about the same first spacing may be provided between adjacent ones of the second plurality of word lines. Related methods are also discussed.

RELATED APPLICATIONS

This U.S. non-provisional patent application claims the benefit ofpriority as a divisional of U.S. application Ser. No. 11/729,169 filedMar. 28, 2007 now U.S. Pat. No. 8,045,383, which claims the benefit ofpriority under 35 U.S.C. §119 of Korean Patent Application No.10-2006-0065040, filed on Jul. 11, 2006. The disclosures of both of theabove referenced applications are hereby incorporated herein byreference in their entireties.

FIELD OF THE INVENTION

The present invention generally relates to electronics, and moreparticularly, to electronic memory devices and related methods.

BACKGROUND

Non-volatile memory devices, such as flash memory devices, may beprovided in a NOR-type configuration or a NAND-type configuration. Byway of example, NOR-type flash memory devices may provide relativelyfast random access, while NAND-type flash memory devices may providerelatively low cost and/or relatively high integration. NOR-type flashmemory devices may thus be used for code memory storage, while NAND-typeflash memory devices may be used for mass memory storage.

NAND-type nonvolatile semiconductor memory devices are discussed, forexample, in U.S. Pat. No. 7,079,437 to Hasama et al. entitled“Nonvolatile Semiconductor Memory Device Having Configuration Of NANDStrings With Dummy Memory Cells Adjacent To Select Transistors.” Moreparticularly, Hasama et al. discusses a nonvolatile semiconductor memorydevice having a plurality of electrically rewritable nonvolatile memorycells connected in series together. A select gate transistor isconnected in series with the serial combination of memory cells, and thememory cell which is located adjacent to the select gate transistor is adummy cell which is not used for data storage. During a data eraseoperation, a same bias voltage that that is applied to the other memorycells is also applied to the dummy cell.

Notwithstanding known nonvolatile memory devices, there continues toexist a need in the art for structures and methods providing more highlyintegrated memory devices.

SUMMARY

According to some embodiments of the present invention, a non-volatilememory device may include a semiconductor substrate including an activeregion at a surface thereof, and first and second memory cell strings onthe active region. The first memory cell string may include a firstplurality of word lines crossing the active region between a firstground select line and a first string select line, and about a samefirst spacing may be provided between adjacent ones of the firstplurality of word lines. The second memory cell string may include asecond plurality of word lines crossing the active region between asecond ground select line and a second string select line, and about thesame first spacing may be provided between adjacent ones of the secondplurality of word lines. The first ground select line may be between thesecond ground select line and the first plurality of word lines, and thesecond ground select line may be between the first ground select lineand the second plurality of word lines. Portions of the active regionbetween the first and second ground select lines may be free of wordlines, and a second spacing between the first and second ground selectlines may be at least about 3 times greater than the first spacing.

The second spacing may be in the range of about 3 to 4 times greaterthan the first spacing. The second spacing may be more than 3 timesgreater than the first spacing, and more particularly, the secondspacing may be at least about 4 times greater than the first spacing.

The first plurality of word lines may include an even number of memorycell word lines and a dummy word line between a first of the even numberof memory cell word lines and the first ground select line. About thesame first spacing may be provided between the ground select line andthe dummy word line, and about the same first spacing may be providedbetween the dummy word line and the first of the even number of memorycell word lines. Moreover, about the same first spacing may be providedbetween a last of the even number of the memory cell word lines and thestring select line.

The first plurality of word lines may include an even number of memorycell word lines and a dummy word line between a first of the even numberof memory cell word lines and the first ground select line. About thesame first spacing may be provided between the dummy word line and thefirst of the even number of memory cell word lines, and a third spacingmay be provided between the ground select line and the dummy word line.Moreover, the third spacing may be greater than the first spacing and nogreater than two times the first spacing, and more particularly, thethird spacing may be in the range of about 1.5 times the first spacingto about 2 times the first spacing.

The first plurality of word lines may include an even number of memorycell word lines, and at least 3 times the first spacing may be providedbetween the ground select line and the first of the even number ofmemory cell word lines. About the first spacing may be provided betweenthe last of the even number of memory cell word lines and the stringselect line, and portions of the active region between the ground selectline and the first of the even number of memory cell word lines may befree of word lines.

Each memory cell of the first and second memory cell strings may includea charge storage layer between the respective word line and the activeregion, and a barrier insulating layer between the charge storage layerand the word line. Moreover, an arrangement of the first memory cellstring may have mirror image symmetry relative to an arrangement of thesecond memory cell string.

According to other embodiments of the present invention, a non-volatilememory device may include a semiconductor substrate including an activeregion at a surface thereof, a ground select line crossing the activeregion, and a string select line crossing the active region and spacedapart from the ground select line. A plurality of memory cell word linesmay cross the active region between the ground select line and thestring select line, and about a same first spacing may be providedbetween adjacent ones of the plurality of word lines. A second spacingmay be provided between a last of the plurality of memory cell wordlines and the string select line, and the second spacing may be greaterthan the first spacing and no greater than two times the first spacing.A dummy word line may be between a first of the plurality of memory cellword lines and the first ground select line, and about the first spacingmay be provided between the dummy word line and the first of theplurality of memory cell word lines. A third spacing may be providedbetween the ground select line and the dummy word line, and the thirdspacing may be greater than the first spacing and no greater than twotimes the first spacing. More particularly, the third spacing may be inthe range of about 1.5 times the first spacing to about 2 times thefirst spacing.

The plurality of memory cell word lines may be a first plurality ofmemory cell word lines, and the non-volatile memory device may furtherinclude a second ground select line crossing the active region, a secondstring select line crossing the active region, and a second plurality ofmemory cell word lines. The first ground select line may be between thesecond ground select line and the first plurality of memory cell wordlines, and the second string select line may be spaced apart from thesecond ground select line with the second ground select line between thesecond string select line and the first ground select line. The secondplurality of memory cell word lines may be between the second groundselect line and the second string select line. Moreover, portions of theactive region between the first and second ground select lines may befree of word lines, and a second spacing between the first and secondground select lines may be at least about 3 times greater than the firstspacing.

The second spacing may be in the range of about 3 to about 4 timesgreater than the first spacing. More particularly, the second spacingmay be more than 3 times greater than the first spacing, and still moreparticularly, the second spacing may be at least about 4 times greaterthan the first spacing.

In addition, a plurality of charge storage layers may be provided withrespective ones of the charge storage layers between each of theplurality of word lines and the active region, and a plurality ofbarrier insulating layers may be provided with respective ones of thebarrier insulating layers between each of the plurality of word linesand the charge storage layers. Moreover, the plurality of memory cellword lines may include an even number of memory cell word lines.

According to some other embodiments of the present invention, anon-volatile memory device may include a semiconductor substrateincluding a active region at a surface thereof, a ground select linecrossing the active region, a string select line crossing the activeregion, and a plurality of memory cell word lines crossing the activeregion. The string select line may be spaced apart from the groundselect line, and the plurality of memory cell word lines may cross theactive region between the ground select line and the string select line.About a same first spacing may be provided between adjacent ones of theplurality of word lines and between a last of the plurality of memorycell word lines and the string select line. A second spacing may beprovided between the ground select line and a first of the plurality ofmemory cell word lines, and the second spacing may be at least threetimes greater than the first spacing. Moreover, portions of the activeregion between the ground select line and the first of the plurality ofmemory cell word lines may be free of word lines. More particularly, thesecond spacing may be about three times greater than the first spacing,and/or the second spacing may be no greater than 4 times the firstspacing.

The plurality of memory cell word lines may be a first plurality ofmemory cell word lines, and the non-volatile memory device furtherinclude a second ground select line crossing the active region, a secondstring select line crossing the active region, and a second plurality ofmemory cell word lines crossing the active region. The first groundselect line may be between the second ground select line and the firstplurality of memory cell word lines, and the second string select linemay be spaced apart from the second ground select line with the secondground select line between the second string select line and the firstground select line. The second plurality of memory cell word lines maybe between the second ground select line and the second string selectline. Moreover, portions of the active region between the first andsecond ground select lines may be free of word lines, and a secondspacing between the first and second ground select lines may be at leastabout 3 times greater than the first spacing.

The second spacing may be in the range of about 3 to about 4 timesgreater than the first spacing, and more particularly, the secondspacing may be about 3 times greater than the first spacing or at leastabout 4 times greater than the first spacing.

In addition, a plurality of charge storage layers may be provided withrespective ones of the charge storage layers between each of theplurality of word lines and the active region, and a plurality ofbarrier insulating layers may be provided with respective ones of thebarrier insulating layers between each of the plurality of word linesand the charge storage layers. Moreover, the plurality of memory cellword lines may include an even number of memory cell word lines.

According to still other embodiments of the present invention, a methodof forming a non-volatile memory device may include forming an etchtarget layer on a substrate. First hard mask patterns may be formedincluding a plurality of odd word line patterns between first and secondselect line patterns, and about a same spacing may be provided betweenthe first select line pattern and a first odd word line pattern, betweenadjacent odd word line patterns, and between a last odd word linepattern and the second select line pattern. Moreover, the first hardmask pattern may include a first material. A sacrificial mask layer maybe formed on the first hard mask pattern with gaps remaining betweenportions of the sacrificial mask layer on sidewalls of adjacent ones ofthe odd word line patterns. The sacrificial mask layer may include asecond material, and the first and second materials may have differentcompositions. Second hard mask patterns may be formed on the sacrificialmask layer, and the second hard mask patterns may include a dummy wordline pattern between the first select line pattern and the first oddword line pattern. The second hard mask patterns may also include evenword line patterns between adjacent odd word line patterns and betweenthe last odd word line pattern and the second select line pattern.Moreover, the second hard mask pattern may include a third material, andthe second and third materials may have different compositions. Portionsof the sacrificial mask layer between the first and second hard maskpatterns may be removed so that portions of the etch target layer areexposed between the first and second hard mask patterns, and portions ofthe etch target layer exposed between the first and second hard maskpatterns may be etched.

The spacing provided between the first select line pattern and the firstodd word line pattern may be about three times a width of the first oddword line pattern. Moreover, the first hard mask patterns may includesilicon nitride, the sacrificial mask layer may include polysilicon, andthe second hard mask patterns may include silicon oxide.

The odd word line patterns may have about a same width, and the spacingbetween adjacent ones of the plurality of the odd word line patterns maybe greater than the width of the odd word line patterns. In addition,forming the etch target layer may include forming a charge storage layeron the substrate, forming a barrier insulating layer on the chargestorage layer, and forming a control gate layer on the barrierinsulating layer.

According to yet other embodiments of the present invention, a method offorming a non-volatile memory device may include forming an etch targetlayer on a substrate. First hard mask patterns may be formed on thesubstrate, and the first hard mask patterns may include a plurality ofeven word line patterns between first and second select line patternsand a dummy word line pattern between the first select line pattern anda first even word line pattern. About a same first spacing may beprovided between the dummy word line pattern and the first even wordline pattern and between adjacent even word line patterns, and a secondspacing may be provided between the first select line pattern and thedummy word line pattern and between a last even word line pattern andthe second select line pattern. Moreover, the second spacing may be lessthan the first spacing, and the first hard mask patterns may include afirst material. A sacrificial mask layer may be formed on the first hardmask patterns with gaps remaining between portions of the sacrificialmask layer on sidewalls of adjacent ones of the even word line patternsand between the dummy word line pattern and the first even word linepattern. The sacrificial mask layer may include a second material, andthe first and second materials may have different compositions. Secondhard mask patterns may be formed in the gaps on the sacrificial layer,and the second hard mask patterns may include odd word line patternsbetween adjacent even word line patterns and between the dummy word linepattern and the first even word line pattern. The second hard maskpatterns may include a third material, and the second and thirdmaterials may have different compositions. Portions of the sacrificialmask layer may be removed between the first and second hard maskpatterns so that portions of the etch target layer are exposed betweenthe first and second hard mask patterns, and a space between the dummyword line pattern and the first select line pattern may be free of anyof the second hard mask patterns. Portions of the etch target layerexposed between the first and second hard mask patterns may then beetched.

The first spacing provided between the dummy word line pattern and afirst even word line pattern and between adjacent even word linepatterns may be about three times a width of the first even word linepattern. The second spacing may be greater than a width of the firsteven word line pattern and no greater than two times the width of thefirst even word line pattern. The second spacing may be in the range ofabout 1.5 times the width of the first even word line pattern to about 2times the width of the first even word line pattern.

The even word line patterns may have about a same width, and the spacingbetween adjacent ones of the plurality of the even word line patternsmay be greater than the width of the even word line patterns. Inaddition, forming the etch target layer may include forming a chargestorage layer on the substrate, forming a barrier insulating layer onthe charge storage layer, and forming a control gate layer on thebarrier insulating layer.

A method of forming a non-volatile memory device may include forming anetch target layer on a substrate and forming first hard mask patterns onthe substrate. The first hard mask patterns may include a plurality ofodd word line patterns between first and second select line patterns,and about a same first spacing may be provided between adjacent odd wordline patterns and between a last odd word line pattern and the secondselect line pattern. A second spacing may be provided between the firstselect line pattern and a first odd word line pattern, and the secondspacing may be greater than the first spacing, and the first hard maskpatterns may include a first material. A sacrificial mask layer may beformed on the first hard mask patterns with gaps remaining betweenportions of the sacrificial mask layer on sidewalls of adjacent firsthard mask patterns, and the sacrificial mask layer may include a secondmaterial, the first and second materials having different compositions.Second hard mask patterns may be formed on the sacrificial layer, andthe second hard mask patterns may include even word line patternsbetween adjacent odd word line patterns and between the last odd wordline pattern and the second select line pattern. A space between thefirst select line pattern and the first odd word line pattern may befree of any of the second hard mask patterns, and the second hard maskpatterns may include a third material with the second and thirdmaterials having different compositions. Portions of the sacrificialmask layer may be removed between the first and second hard maskpatterns so that portions of the etch target layer are exposed betweenthe first and second hard mask patterns. Portions of the etch targetlayer exposed between the first and second hard mask patterns may thenbe etched.

The same first spacing may be about three times a width of the first oddword line pattern. In addition, forming the etch target layer mayinclude forming a charge storage layer on the substrate, forming abarrier insulating layer on the charge storage layer, and forming acontrol gate layer on the barrier insulating layer.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a plan view of a non-volatile memory device according to someembodiments of the present invention.

FIG. 1B is a cross-sectional view taken along line I-I′ of FIG. 1A.

FIG. 1C is an enlarged cross-sectional view illustrating ground inducedleakage current during a programming operation.

FIG. 1D is an enlarged cross-sectional view illustrating couplingcapacitance during an erase operation.

FIG. 2A is a plan view of a non-volatile memory device according to someembodiments of the present invention.

FIG. 2B is a cross-sectional view taken along section line II-II′ ofFIG. 2A.

FIG. 3A is a plan view of a non-volatile memory device according to someother embodiments of the present invention.

FIG. 3B is a cross-sectional view taken along section line III-III′ ofFIG. 3A.

FIG. 4A is a plan view of a non-volatile memory device according to someother embodiments of the present invention.

FIG. 4B is a cross-sectional view taken along section line IV-IV′ ofFIG. 4A.

FIGS. 5A-D are cross-sectional views illustrating operations of formingnon-volatile memory structures of FIGS. 2A-B according to embodiments ofthe present invention.

FIGS. 6A-D are cross-sectional views illustrating operations of formingnon-volatile memory structures of FIGS. 3A-B according to embodiments ofthe present invention.

FIGS. 7A-D are cross-sectional views illustrating operations of formingnon-volatile memory structures of FIGS. 4A-B according to embodiments ofthe present invention.

DETAILED DESCRIPTION

The present invention is described more fully hereinafter with referenceto the accompanying drawings, in which embodiments of the presentinvention are shown. This invention may, however, be embodied in manydifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the present invention to those skilled in the art.In the drawings, the sizes and relative sizes of layers and regions maybe exaggerated for clarity. Like numbers refer to like elementsthroughout.

It will be understood that when an element or layer is referred to asbeing “on”, “connected to” or “coupled to” another element or layer, itcan be directly on, connected or coupled to the other element, or layeror intervening elements or layers may be present. In contrast, when anelement is referred to as being “directly on,” “directly connected to”or “directly coupled to” another element or layer, there are nointervening elements or layers present. As used herein, the term“and/or” includes any and all combinations of one or more of theassociated listed items.

It will be understood that, although the terms first, second, third etc.may be used herein to describe various elements, components, regions,layers and/or sections, these elements, components, regions, layersand/or sections should not be limited by these terms. These terms areonly used to distinguish one element, component, region, layer orsection from another region, layer or section. Thus, a first element,component, region, layer or section discussed below could be termed asecond element, component, region, layer or section without departingfrom the teachings of the present invention.

Spatially relative terms, such as “beneath”, “below”, “lower”, “above”,“upper” and the like, may be used herein for ease of description todescribe one element or feature's relationship to another element(s) orfeature(s) as illustrated in the figures. It will be understood that thespatially relative terms are intended to encompass differentorientations of the device in use or operation in addition to theorientation depicted in the figures. For example, if the device in thefigures is turned over, elements described as “below” or “beneath” otherelements or features would then be oriented “above” the other elementsor features. Thus, the exemplary term “below” can encompass both anorientation of above and below. The device may be otherwise oriented(rotated 90 degrees or at other orientations) and the spatially relativedescriptors used herein interpreted accordingly. Also, as used herein,“lateral” refers to a direction that is substantially orthogonal to avertical direction.

The terminology used herein is for the purpose of describing particularembodiments only, and is not intended to be limiting of the presentinvention. As used herein, the singular forms “a”, “an” and “the” areintended to include the plural forms as well, unless the context clearlyindicates otherwise. It will be further understood that the terms“comprises” and/or “comprising,” when used in this specification,specify the presence of stated features, integers, steps, operations,elements, and/or components, but do not preclude the presence oraddition of one or more other features, integers, steps, operations,elements, components, and/or groups thereof.

Example embodiments of the present invention are described herein withreference to cross-section illustrations that are schematicillustrations of idealized embodiments (and intermediate structures) ofthe invention. As such, variations from the shapes of the illustrationsas a result, for example, of manufacturing techniques and/or tolerances,are to be expected. Thus, embodiments of the present invention shouldnot be construed as limited to the particular shapes of regionsillustrated herein but are to include deviations in shapes that result,for example, from manufacturing. For example, an implanted regionillustrated as a rectangle will, typically, have rounded or curvedfeatures and/or a gradient of implant concentration at its edges ratherthan a binary change from implanted to non-implanted region. Likewise, aburied region formed by implantation may result in some implantation inthe region between the buried region and the surface through which theimplantation takes place. Thus, the regions illustrated in the figuresare schematic in nature and their shapes are not intended to illustratethe actual shape of a region of a device and are not intended to limitthe scope of the present invention.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this invention belongs.Accordingly, these terms can include equivalent terms that are createdafter such time. It will be further understood that terms, such as thosedefined in commonly used dictionaries, should be interpreted as having ameaning that is consistent with their meaning in the presentspecification and in the context of the relevant art, and will not beinterpreted in an idealized or overly formal sense unless expressly sodefined herein. All publications, patent applications, patents, andother references mentioned herein are incorporated by reference in theirentirety.

As shown in FIGS. 1A and 1B, a flash memory device may include aplurality of parallel active regions ACT in a semiconductor substrateseparated by device isolation layers. In addition, ground select linesGSL, string select lines SSL, and word lines WL may cross the activeregions ACT. More particularly, a respective charge storage gate may beprovided between each word line WL and each active region ACT to providea respective memory cell at each intersection of a word line WL and anactive region ACT. Moreover, a plurality of memory cells along an activeregion ACT between a ground select line GSL and a string select line SSLmay define a memory cell string. As further shown in FIGS. 1A and 1B,adjacent memory cell strings may be separated by two ground select linesGSL or by two string select lines SSL.

As shown in the enlarged cross-sectional views of FIGS. 1C and 1D, agate insulating layer GIL may be provided between the ground select lineGSL and the active region ACT of the semiconductor substrate SUB. Inaddition, a charge storage gate CSG may be provided between the wordline WL1 and the active region ACT of the substrate SUB, a tunnelinsulating layer TIL may be provided between the charge storage gate CSGand the active region ACT, and a barrier insulating layer BIL may beprovided between the charge storage gate CSG and the word line WL1.

During a programming operation (for a memory cell other than that shownin FIG. 1C), 0 volts may be applied to the ground select line GSL and apass voltage Vpass may be applied to the non-selected word line WL1 asshown in FIG. 1C. In addition, a program voltage Vpgm may be applied toa selected word line (not shown) corresponding to a memory cell(s) to beprogrammed. A gate voltage of the ground select transistor (defined bythe ground select line GSL and the gate insulating layer GIL) may thusbe 0 volts while a drain voltage of the ground select transistor may beabout 10 volts resulting in a gate induced leakage current GIDL.

During an erase operation, the ground select line GSL may be allowed tofloat, and an erase voltage Vers of about 20 volts may be applied to ap-well of the substrate SUB, and 0 volt may be applied to the word lineWL1, as shown in FIG. 1D. Accordingly, the erase voltage Vers of 20volts applied to the p-well may boost a potential of the ground selectline GSL, and a potential of the charge storage gate CSG (adjacent tothe ground select line GSL) may increase due to capacitive coupling Cpbetween the ground select line GSL and the charge storage gate CSG. Anundesirable erase disturbance may thus result at the charge storage gateCSG and/or the word line WL1.

FIG. 2A is a plan view of a non-volatile memory device 20 (such as aflash memory device) according to some embodiments of the presentinvention, and FIG. 2B is a cross-sectional view taken along sectionline II-II′ of FIG. 2A. The flash memory device 20 may include aplurality of parallel active regions ACT in a semiconductor substrateSUB separated by device isolation layers. In addition, ground selectlines GSL₀₋₂, string select lines SSL₀₋₂, dummy word lines WL_(d), andmemory cell word lines WL_(1-2n) (where n is an integer) may cross theactive regions ACT. More particularly, a respective charge storage gatemay be provided between each memory cell word line WL_(1-2n) and eachactive region ACT to provide a respective memory cell at eachintersection of a memory cell word line WL_(1-2n) and an active regionACT. Similarly, a charge storage gate may be provided between each dummyword line WL_(d) and active region ACT so that the structures of thedummy word lines WL_(d) and the memory cell word lines WL_(1-2n) are thesame.

An even number of memory cell word lines WL_(1-2n) along an activeregion ACT between a ground select line GSL and a string select line SSL(e.g., between GSL₁ and SSL₁) may define a memory cell string includingan even number of memory cells. As further shown in FIGS. 2A-B, adjacentmemory cell strings may be separated by two ground select lines GSL(e.g., GSL₀ and GSL₁) or by two string select lines SSL (e.g., SSL₁ andSSL₂). More particularly, 2^(k) (where k is a positive integer) memorycell word lines WL_(1-2n) may define a memory cell string including2^(k) memory cells used to store data. The dummy word line WL_(d),however, is not used to store data.

Moreover, an order of memory cell word lines WL_(1-2n) and dummy wordline WL_(d) of adjacent memory cell strings may have a mirror imagesymmetry. For example, an order of memory cell word lines WL_(1-2n) anddummy word line WL_(d) between ground select line GSL₀ and string selectline SSL₀ may have mirror image symmetry relative to an order of memorycell word lines WL_(1-2n) and dummy word line WL_(d) between groundselect line GSL₁ and string select line SSL₁. Similarly, an order ofmemory cell word lines WL_(1-2n) and dummy word line WL_(d) betweenground select line GSL₁ and string select line SSL₁ may have mirrorimage symmetry relative to an order of memory cell word lines WL_(1-2n)and dummy word line WL_(d) between ground select line GSL₂ and stringselect line SSL₂.

By providing a dummy word line WL_(d) between a ground select line GSLand a first memory cell word line WL₁ of a memory cell string, a groundinduced leakage current and/or an erase disturbance at the first memorycell word line WL₁ may be reduced. Moreover, a controller of thenon-volatile memory device may be coupled to the ground select lines,the string select lines, the memory cell word lines, and the dummy wordlines. During an erase operation, for example, the controller may beconfigured to allow the ground select line GSL₁ to float, to apply anerase voltage Vers of about 20 volts to a p-well of the substrate SUB,and to apply 0 volts to the memory cell word lines WL_(1-2n). Inaddition, the controller may be configured to apply a bias voltage Vb tothe dummy word line WL_(d) with the bias voltage Vb being between asupply voltage Vcc and a pass voltage Vpass (i.e., Vcc<Vb<Vpass) tothereby reduce an erase disturbance at the first memory cell word lineWL₁ and/or at respective charge storage layers.

During a write (or program) operation, the controller may be configuredto apply the supply voltage Vcc to the ground select line GSL₁, to apply0 volts to a p-well of the substrate SUB, to apply a pass voltage Vpassto the non-selected word lines, and to apply a program voltage Vpgm tothe selected word line. In addition, the controller may be configured toapply a bias voltage Vb to the dummy word line WL_(d) with the biasvoltage Vb being between the supply voltage Vcc and the pass voltageVpass (i.e., Vcc<Vb<Vpass) to thereby reduce ground induced leakagecurrent at the ground select line adjacent to the dummy word line.

As shown in FIGS. 2A-B, the dummy word line WL_(d) and each of thememory cell word lines WL₁ to WL_(2n) may have about a same width F₁. Inaddition, about a same width/spacing W₁ may separate a gate selectionline GSL and an adjacent dummy word line WL_(d), about the samewidth/spacing W₁ may separate a dummy word line WL_(d) and an adjacentfirst memory cell word line WL₁, about the same width/spacing W₁ mayseparate adjacent memory cell word lines WL_(x) and WL_(x+1), and aboutthe same width/spacing W₁ may separate a last memory cell word lineWL_(2n) and an adjacent string select line SSL. Moreover, the widths F₁and W₁ may be about the same, and more particularly, each of the widthsF₁ and W₁ may be about one fourth (¼) of a period P₁ defined by adjacenteven memory cell word lines WL_(even) and WL_(even+2) (i.e., even memorycell word lines separated by only one odd memory cell word line), ordefined by adjacent odd memory cell word lines WL_(odd) and WL_(odd+2)(i.e., odd memory cell word lines separated by only one even memory cellword line). As further shown in FIGS. 2A-B, adjacent ground selectionlines GSL₀ and GSL₁ may be separated by about a width/spacing W₂, andadjacent string selection lines SSL₀ and SSL₁ may be separated by aboutthe same width/spacing W₂. The width/spacing W₂ may be at least about 3times greater than the width/spacing W₁.

Each memory cell word line WL₁ to WL_(2n) may thus provide a respectivecontrol electrode for a non-volatile memory cell (such as a flash memorycell) of a memory cell string on a same active region ACT between aground select line (e.g., GSL₁) and a string select line (e.g., SSL₁).Each non-volatile memory cell may also include a charge storage layerbetween the respective memory cell word line and active region, a tunnelinsulating layer between the active region and the charge storage layer,and a barrier insulating layer between the memory cell word line and thecharge storage layer.

Each dummy word line WL_(d) may have a structure the same as thatdiscussed above with respect to the memory cell word lines (with atunnel insulating layer, a charge storage layer, and a barrierinsulating layer between each dummy word line and respective activeregions). The dummy cell word lines (and associated tunnel insulatinglayers, charge storage layers, and barrier insulating layers), however,are not used to store data, but are instead provided to reduce groundinduced leakage current at the adjacent ground select line duringprogramming operations and/or to reduce erase bias at the adjacentmemory cell during erase operations.

The pattern of ground select lines GSL, dummy word lines WL_(d), memorycell word lines WL₁ to WL_(2n), and string select lines SSL may beformed using self-aligned double patterning as discussed in greaterdetail below. For example, the ground select lines GSL, the stringselect lines SSL, and the odd memory cell word lines (WL₁, WL₃, WL₅ . .. WL_(2n−1)) may be formed corresponding to a pattern of aphotolithography mask, and the dummy word lines WL_(d) and the evenmemory cell word lines (WL₂, WL₄, WL₆ . . . WL_(2n)) may be formed usingself-aligned double patterning.

According to some embodiments of the present invention illustrated inFIGS. 2A-B, a first memory cell string on the active region ACT mayinclude a first plurality of memory cell word lines WL₁ to WL_(2n)crossing the active region ACT between the first ground select line GSL₁and the first string select line SSL₁, and about a same first spacing W₁may be provided between adjacent ones of the first plurality of wordlines. In addition, a second memory cell string on the active region ACTmay include a second plurality of word lines WL₁ to WL_(2n) crossing theactive region ACT between a second ground select line GSL₀ and a secondstring select line SSL₁, and about the same first spacing W₁ may beprovided between adjacent ones of the second plurality of word lines.More particularly, the first ground select line GSL₁ may be between thesecond ground select line GSL₀ and the first plurality of word lines,and the second ground select line GSL₀ may be between the first groundselect line GSL₁ and the second plurality of word lines. Moreover,portions of the active region ACT between the first and second groundselect lines GSL₁ and GSL₀ may be free of word lines, and the secondspacing W₂ between the first and second ground select lines GSL₁ andGSL₀ may be at least about 3 times greater than the first spacing W₁.For example, the second spacing W₂ may be between about 3 and 4 timesgreater than the first spacing W₁, and more particularly, the secondspacing W₂ may be more than 3 times greater than the first spacing W₁,and still more particularly, more than 4 times greater than the firstspacing W₁.

In addition, the dummy word line WL_(d) may be provided between thefirst memory cell word line WL₁ and the first ground select line GSL₁,and about the same first spacing W₁ may be provided between the firstground select line GSL₁ and the dummy word line WL_(d). About the samefirst spacing W₁ may also be provided between the dummy word line WL_(d)and the first memory cell word line WL₁, and between the last memorycell word line WL_(2n−1) and the string select line SSL₁.

FIGS. 5A-D are cross-sectional views illustrating operations of formingthe non-volatile memory structures of FIGS. 2A-B using self-aligneddouble patterning according to some embodiments of the presentinvention. As shown in FIG. 5A, a substrate 50 may include an etchtarget layer 52 thereon, and the etch target layer 52 may include layersof materials used to form the memory cells, word lines, selectiontransistors, and selection lines of FIGS. 2A-B.

More particularly, the target layer may include a tunnel insulatinglayer (such as a layer of silicon oxide), a charge storage gate layer(such as a layer of polysilicon or silicon nitride), a barrierinsulating layer (such as a layer of silicon oxide or other dielectricmaterial different than the charge storage gate layer), and conductivelayer (such as a layer of polysilicon and/or metal). The charge storagelayer may be between the conductive layer and the substrate with thetunnel insulating layer separating the charge storage layer and thesubstrate and with the barrier insulating layer separating the chargestorage layer and the conductive layer. In addition, a first hard masklayer 55 may be formed on the etch target layer 52, and the first hardmask layer 55 may include a silicon nitride layer 56 on a pad oxidelayer 54.

A photoresist layer on the first hard mask layer 55 may be patternedusing the photo-mask 100 to provide the photoresist pattern 58 includingodd word line photoresist patterns 58 w, ground select line photoresistpatterns 58 g, and string select line photoresist patterns 58 s. Moreparticularly, the photo-mask 100 may include a photo-mask pattern 104 ona transparent substrate 102. The photo-mask pattern 104 may include oddword line photo-mask patterns 104 w corresponding to odd word linephotoresist patterns 58 w, ground select line photo-mask patterns 104 gcorresponding to ground select line photoresist patterns 58 g, andstring select line photo-mask patterns 104 s corresponding to stringselect line photoresist patterns 58 s.

As further shown in FIG. 5A, adjacent odd word line photo-mask patterns104 w may be spaced apart by about a width/spacing W₁₁, and adjacent oddword line photoresist patterns 58 w may be spaced apart by about thewidth/spacing W₁₁. A first of the odd word line photo-mask patterns 104w may be spaced apart from an adjacent ground select line photo-maskpattern 104 g by about the width/spacing W₁₁, and a last of the odd wordline photo-mask patterns 104 w may be spaced apart from an adjacentstring select line photo-mask pattern 104 s by about the width/spacingSimilarly, a first of the odd word line photoresist patterns 58 w may bespaced apart from an adjacent ground select line photoresist pattern 58g by about the width/spacing W₁₁, and a last of the odd word linephoto-mask patterns 58 w may be spaced apart from an adjacent stringselect line photo-mask pattern 58 s by about the width/spacing W₁₁.

Moreover, each of the odd word line photo-mask patterns 104 w and eachof the odd word line photoresist patterns 58 w may have a width of aboutF₁, and the width/spacing W₁₁ may be about three times the width F₁. Inaddition, adjacent ones of the odd word line photo-mask patterns 104 wand adjacent ones of the odd word line photoresist patterns 58 w maydefine a period P₁, and the period P₁ may be about 4 times the width F₁.The width F₁ may be a minimum feature size available from thephotolithography technology being used. Adjacent ground select linephoto-mask patterns 104 g, adjacent string select line photo-maskpatterns 104 s, adjacent ground select line photoresist patterns 58 g,and adjacent string select line photoresist patterns 58 s may beseparated by a width/spacing W₂, and the width/spacing W₂ may be greaterthan four times the width F₁. Moreover, the second spacing W₂ may be atleast about 3 times greater than the first spacing W₁. For example, thesecond spacing W₂ may be between about 3 and 4 times greater than thefirst spacing W₁, and more particularly, the second spacing W₂ may bemore than 3 times greater than the first spacing W₁, and still moreparticularly, more than 4 times greater than the first spacing W₁.

More particularly, a continuous photoresist layer may be selectivelyexposed to radiation through the photomask 100 and then developed toprovide the photoresist pattern 58 of FIG. 5A. Accordingly, anarrangement of the photoresist pattern 58 is defined by an arrangementof the photo-mask pattern 104. In addition, the photoresist pattern 58corresponds to a pattern of gate select lines, string select lines, andodd word lines discussed above with respect to FIGS. 2A-B.

Portions of the first hard mask layer 55 (including silicon nitridelayer 56 and pad oxide layer 54) exposed by the photoresist pattern 58may be selectively removed (for example, using dry etching) to provide afirst hard mask pattern 60 (including ground select line hard maskpatterns 60 g, string select line hard mask patterns 60 s, and odd wordline hard mask patterns 60 w) as shown in FIG. 5B. If the first hardmask layer 55 includes separate layers 54 and 56, each element of thefirst hard mask pattern 60 may also include separate layers 54 and 56.About a same spacing/width W₁₁ may be provided between a ground selectline hard mask pattern 60 g and a first odd word line hard mask pattern60 w, between adjacent odd word line hard mask patterns 60 w, andbetween a, last odd word line hard mask pattern 60 w and a string selectline hard mask pattern 60 s. Each element of the first hard mask pattern60 may include a layer of silicon nitride and/or silicon oxide. Afterselectively removing portions of the first hard mask layer, thephotoresist pattern 58 may be removed.

As further shown in FIG. 5B, a sacrificial mask layer 62 may be formedon the first hard mask pattern 60 and on portions of the etch targetlayer 52 exposed by the first hard mask pattern 60, and the sacrificialmask layer 62 and the first hard mask pattern 60 may comprise differentmaterials. For example, upper layers 56 of the first hard mask pattern60 may be a layer of silicon nitride, and the sacrificial mask layer 62may be a layer of polysilicon. Moreover, a thickness of the sacrificialmask layer 62 may be provided so that: gaps remain between portions ofthe sacrificial mask layer 62 on sidewalls of adjacent ones of the oddword line hard mask patterns 60 w; gaps remain between portions of thesacrificial mask layer 62 on sidewalls of adjacent ground select linehard mask patterns 60 g; gaps remain between portions of the sacrificialmask layer 62 on sidewalls of adjacent string select line hard maskpatterns 60 s; gaps remain between portions of the sacrificial masklayer 62 on sidewalls of adjacent select line hard mask patterns 60 gand first odd word line hard mask patterns 60 w; and gaps remain betweenportions of the sacrificial mask layer 62 on sidewalls of adjacentselect line hard mask patterns 60 s and last odd word line hard maskpatterns 60 w.

A thickness of the sacrificial mask layer 62 on sidewalls of the firsthard mask patterns 60 w, 60 g, and 60 s may be about the same as thewidth/spacing W₁ between adjacent word lines WL_(x) and WL_(x+1) shownin FIGS. 2A-B. A width/spacing of a gap remaining between portions ofthe sacrificial mask layer 62 on adjacent odd word line mask patterns60W may be about the same as a width F₁ of an even word line WL₂, WL₄, .. . WL_(2n) shown in FIGS. 2A-B.

After forming the sacrificial mask layer 62, a second hard mask layer 64may be formed on the sacrificial mask layer 62, as further shown in FIG.5B. Moreover, the second hard mask layer 64 may be a layer of siliconoxide, and the second hard mask layer 64 may have a thickness that is atleast one half of the width F₁ to thereby fill gaps in the sacrificialmask layer 62 between odd word line hard mask patterns 60 w. Becausewider gaps are provided between adjacent ground select line hard maskpatterns 60 g and between adjacent string select line hard mask patterns60 s, however, gaps 68 may remain in the second hard mask layer 64. If athickness of the second hard mask layer 64 is about the width F₁ of aword line, adjacent ground select line patterns 60 g and adjacent stringselect line patterns 60 s may be separated by a width/spacing greaterthan four times F₁.

The second hard mask layer 64 may then be subjected to an etch backoperation to remove portions of the hard mask layer 64 from betweenadjacent ground select line hard mask patterns 60 g, from betweenadjacent string select line hard mask patterns 60 s, and from uppersurfaces of the sacrificial mask layer 62, as shown in FIG. 5C. Portionsof the second hard mask layer 64 remaining after the etch back operationmay thus have about the thickness F₁. More particularly, portions of thesecond hard mask layer 64 remaining after the etch back operation maydefine a second hard mask pattern 70 on the sacrificial mask layer 62.The second hard mask pattern 70 may include a dummy word line pattern 70d between the ground select line pattern 60 g and the first odd wordline pattern 60 w, and even word line patterns 70 w between adjacent oddword line patterns 60 w and between the last odd word line pattern 60 wand the string select line pattern 60 s.

Exposed portions of the sacrificial mask layer 62 may then be removed(for example, using a dry etch) as shown in FIG. 5D to expose portionsof the etch target layer 52 not covered by the first and/or second hardmask patterns 60 and/or 70. Exposed portions of the etch target layer 52may then be removed (for example, using a dry etch) using the first andsecond hard mask patterns 60 and 70 as an etch mask, and the first andsecond hard mask patterns 60 and 70 may then be removed to provide thestructure of FIGS. 2A-B.

FIG. 3A is a plan view of a non-volatile memory device 30 (such as aflash memory device) according to some embodiments of the presentinvention, and FIG. 3B is a cross-sectional view taken along sectionline II-II′ of FIG. 3A. The flash memory device 30 may include aplurality of parallel active regions ACT in a semiconductor substrateSUB separated by device isolation layers. In addition, ground selectlines GSL₀₋₂, string select lines SSL₀₋₂, dummy word lines WL_(d), andmemory cell word lines WL_(1-2n) (where n is an integer) may cross theactive regions ACT. More particularly, a respective charge storage gatemay be provided between each memory cell word line WL_(1-2n) and eachactive region ACT to provide a respective memory cell at eachintersection of a memory cell word line WL_(1-2n) and an active regionACT. Similarly, a charge storage gate may be provided between each dummyword line WL_(d) and active region ACT so that the structures of thedummy word lines WL_(d) and the memory cell word lines WL_(1-2n) are thesame.

An even number of memory cell word lines WL_(1-2n) along an activeregion ACT between a ground select line GSL and a string select line SSL(e.g., between GSL₁ and SSL₁) may define a memory cell string includingan even number of memory cells. As further shown in FIGS. 3A-B, adjacentmemory cell strings may be separated by two ground select lines GSL(e.g., GSL₀ and GSL₁) or by two string select lines SSL (e.g., SSL₁ andSSL₂). More particularly, 2^(k) (where k is a positive integer) memorycell word lines WL_(1-2n) may define a memory cell string including2^(k) memory cells used to store data. The dummy word line WL_(d),however, is not used to store data.

Moreover, an order of memory cell word lines WL_(1-2n) and dummy wordline WL_(d) of adjacent memory cell strings may have a mirror imagesymmetry. For example, an order of memory cell word lines WL_(1-2n) anddummy word line WL_(d) between ground select line GSL₀ and string selectline SSL₀ may have mirror image symmetry relative to an order of memorycell word lines WL_(1-2n) and dummy word line WL_(d) between groundselect line GSL₁ and string select line SSL₁. Similarly, an order ofmemory cell word lines WL_(1-2n) and dummy word line WL_(d) betweenground select line GSL₁ and string select line SSL₁ may have mirrorimage symmetry relative to an order of memory cell word lines WL_(1-2n)and dummy word line WL_(d) between ground select line GSL₂ and stringselect line SSL₂.

By providing a dummy word line WL_(d) between a ground select line GSLand a first memory cell word line WL₁ of a memory cell string, a groundinduced leakage current and/or an erase disturbance at the first memorycell word line WL₁ may be reduced. Moreover, a controller of thenon-volatile memory device may be coupled to the ground select lines,the string select lines, the memory cell word lines, and the dummy wordlines. During an erase operation, for example, the controller may beconfigured to allow the ground select line GSL₁ to float, to apply anerase voltage Vers of about 20 volts to a p-well of the substrate SUB,and to apply 0 volts to the memory cell word lines WL_(1-2n). Inaddition, the controller may be configured to apply a bias voltage Vb tothe dummy word line WL_(d) with the bias voltage Vb being between asupply voltage Vcc and a pass voltage Vpass (i.e., Vcc<Vb<Vpass) tothereby reduce an erase disturbance at the first memory cell word lineWL₁ and/or at respective charge storage layers.

During a write (or program) operation, the controller may be configuredto apply the supply voltage Vcc to the ground select line GSL₁, to apply0 volts to a p-well of the substrate SUB, to apply a pass voltage Vpassto the non-selected word lines, and to apply a program voltage Vpgm tothe selected word line. In addition, the controller may be configured toapply a bias voltage Vb to the dummy word line WL_(d) with the biasvoltage Vb being between the supply voltage Vcc and the pass voltageVpass (i.e., Vcc<Vb<Vpass) to thereby reduce ground induced leakagecurrent at the ground select line adjacent to the dummy word line.

As shown in FIGS. 3A-B, the dummy word line WL_(d) and each of thememory cell word lines WL₁ to WL_(2n) may have about a same width F₁. Inaddition, about a same width/spacing W₁ may separate a dummy word lineWL_(d) and an adjacent first memory cell word line WL₁, and about thesame width/spacing W₁ may separate adjacent memory cell word linesWL_(x) and WL_(x+1). Moreover, the widths F₁ and W₁ may be about thesame, and more particularly, each of the widths F₁ and W₁ may be aboutone fourth (¼) of a period P₁ defined by adjacent even memory cell wordlines WL_(even) and WL_(even+2) (i.e., even memory cell word linesseparated by only one odd memory cell word line), or defined by adjacentodd memory cell word lines WL_(odd) and WL_(odd+2) (i.e., odd memorycell word lines separated by only one even memory cell word line).

As further shown in FIGS. 3A-B, adjacent ground selection lines GSL₀ andGSL₁ may be separated by about a width/spacing W₂, and adjacent stringselection lines SSL₀ and SSL₁ may be separated by about the samewidth/spacing W₂. Moreover, the second width/spacing W₂ may be at leastabout 3 times greater than the first spacing W₁. For example, the secondspacing W₂ may be between about 3 and 4 times greater than the firstspacing W₁, and more particularly, the second spacing W₂ may be morethan 3 times greater than the first spacing W₁, and still moreparticularly, more than 4 times greater than the first spacing W₁.Furthermore, a width/spacing W₃ may separate a gate selection line GSLand an adjacent dummy word line WL_(d), and about the same width/spacingW₃ may separate a last memory cell word line WL_(2n) and an adjacentstring select line SSL. The width/spacing W₃ may be greater than thewidth/spacing W₁, and more particularly, the width/spacing W₃ may begreater than the width/spacing W₁ and less than two times W₁ (i.e.,W₁<W₃<2×W₁), and still more particularly, the width/spacing W₃ may begreater than 1.5 times the width/spacing W₁ and less than two times W₁(i.e., 1.5×W₁<W₃<2×W₁).

Each memory cell word line WL₁ to WL_(2n) may thus provide a respectivecontrol electrode for a non-volatile memory cell (such as a flash memorycell) of a memory cell string on a same active region ACT between aground select line (e.g., GSL₁) and a string select line (e.g., SSL₁).Each non-volatile memory cell may also include a charge storage layerbetween the respective memory cell word line and active region, a tunnelinsulating layer between the active region and the charge storage layer,and a barrier insulating layer between the memory cell word line and thecharge storage layer.

Each dummy word line WL_(d) may have a structure the same as thatdiscussed above with respect to the memory cell word lines (with atunnel insulating layer, a charge storage layer, and a barrierinsulating layer between each dummy word line and respective activeregions). The dummy cell word lines (and associated tunnel insulatinglayers, charge storage layers, and barrier insulating layers), however,are not used to store data, but are instead provided to reduce groundinduced leakage current at the adjacent ground select line duringprogramming operations and/or to reduce erase bias at the adjacentmemory cell during erase operations.

The pattern of ground select lines GSL, dummy word lines WL_(d), memorycell word lines WL₁ to WL_(2n), and string select lines SSL may beformed using self-aligned double patterning as discussed in greaterdetail below. For example, the ground select lines GSL, the stringselect lines SSL, the dummy word lines WL_(d), and the even memory cellword lines (WL₂, WL₄, WL₆ . . . WL_(2n)) may be formed corresponding toa pattern of a photolithography mask, and the odd memory cell word lines(WL₁, WL₃, WL₅ . . . WL_(2n−1)) may be formed using self-aligned doublepatterning.

According to some embodiments of the present invention illustrated inFIGS. 3A-B, a first memory cell string on an active region ACT mayinclude a first plurality of word lines WL₁ to WL_(2n) crossing theactive region ACT between a first ground select line GSL₁ and a firststring select line SSL₁, and about a same first spacing W₁ may beprovided between adjacent ones of the first plurality of word lines WL₁to WL_(2n). A second memory cell string on the active region ACT mayinclude a second plurality of word lines WL₁ to WL_(2n) crossing theactive region ACT between a second ground select line GSL₀ and a secondstring select line SSL₀, and about the same first spacing W₁ may beprovided between adjacent ones of the second plurality of word lines WL₁to WL_(2n). The first ground select line GSL₁ may be between the secondground select line GSL₀ and the first plurality of word lines, and thesecond ground select line GSL₀ may be between the first ground selectline GSL₁ and the second plurality of word lines. Moreover, portions ofthe active region ACT between the first and second ground select linesGSL₁ and GSL₀ may be free of word lines, and a second spacing W₂ betweenthe first and second ground select lines GSL₁ and GSL₀ may be at leastabout 3 times greater than the first spacing W₁. For example, the secondspacing W₂ may be between about 3 and 4 times greater than the firstspacing W₁, and more particularly, the second spacing W₂ may be morethan 3 times greater than the first spacing W₁, and still moreparticularly, more than 4 times greater than the first spacing W₁.

In addition, the first plurality of word lines WL₁ to WL_(2n) mayinclude an even number of memory cell word lines, and a dummy word lineWL_(d) may be provided between a first of the memory cell word lines WL₁to WL₂, and the ground select line GSL₁. About the same first spacing W₁may be provided between the dummy word line WL_(d) and the first of thememory cell word lines WL₁ to WL_(2n). Moreover, a third spacing W₃ maybe provided between the ground select line GSL₁ and the dummy word lineWL_(d), and the third spacing W₃ may be greater than the first spacingW₁ and no greater than two times the first spacing W₁ (i.e.,W₁<W₃<2×W₁).

FIGS. 6A-D are cross-sectional views illustrating operations of formingthe non-volatile memory structures of FIGS. 3A-B using self-aligneddouble patterning according to some embodiments of the presentinvention. As shown in FIG. 6A, a substrate 150 may include an etchtarget layer 152 thereon, and the etch target layer 152 may includelayers of materials used to form the memory cells, word lines, selectiontransistors, and selection lines of FIGS. 3A-B.

More particularly, the etch target layer 152 may include a tunnelinsulating layer (such as a layer of silicon oxide), a charge storagegate layer (such as a layer of polysilicon or silicon nitride), abarrier insulating layer (such as a layer of silicon oxide or otherdielectric material different than the charge storage gate layer), andconductive layer (such as a layer of polysilicon and/or metal). Thecharge storage layer may be between the conductive layer and thesubstrate with the tunnel insulating layer separating the charge storagelayer and the substrate and with the barrier insulating layer separatingthe charge storage layer and the conductive layer. In addition, a firsthard mask layer 155 may be formed on the etch target layer 152, and thefirst hard mask layer 155 may include a silicon nitride layer 156 on apad oxide layer 154.

A photoresist layer on the first hard mask layer 155 may be patternedusing the photo-mask 200 to provide the photoresist pattern 158including dummy word line photoresist pattern 158 d, even word linephotoresist patterns 158 w, ground select line photoresist patterns 158g, and string select line photoresist patterns 158 s. More particularly,the photo-mask 200 may include a photo-mask pattern 204 on a transparentsubstrate 202. The photo-mask pattern 204 may include dummy word linephoto-mask patterns 204 d corresponding to dummy word line photoresistpatterns 158 d, even word line photo-mask patterns 204 w correspondingto even word line photoresist patterns 158 w, ground select linephoto-mask patterns 204 g corresponding to ground select linephotoresist patterns 158 g, and string select line photo-mask patterns204 s corresponding to string select line photoresist patterns 158 s.

As further shown in FIG. 6A, adjacent even word line photo-mask patterns204 w may be spaced apart by about a width/spacing W₁₁, and adjacenteven word line photoresist patterns 158 w may be spaced apart by aboutthe width/spacing W₁₁. A first of the even word line photo-mask patterns204 w may be spaced apart from an adjacent dummy word line photo-maskpattern 204 d by about the width/spacing W₁₁, and a first of the evenword line photoresist patterns 158 w may be spaced apart from anadjacent dummy word line photoresist pattern 158 d by about thewidth/spacing W₁₁. A dummy word line photo-mask pattern 204 d may bespaced apart from an adjacent ground select line photo-mask pattern 204g by about the width/spacing W₃, and a last of the even word linephoto-mask patterns 204 w may be spaced apart from an adjacent stringselect line photo-mask pattern 204 s by about the width/spacing W₃.Similarly, a dummy word line photoresist pattern 158 d may be spacedapart from an adjacent ground select line photoresist pattern 158 g byabout the width/spacing W₃, and a last of the even word line photo-maskpatterns 158 w may be spaced apart from an adjacent string select linephoto-mask pattern 158 s by about the width/spacing W₃.

Moreover, each of the even word line photo-mask patterns 204 w and eachof the even word line photoresist patterns 158 w may have a width ofabout F₁, and the width/spacing W₃ may be in the range of at least aboutthe with F₁ to no greater than about two times the width F₁(F₁#W₃#2×F₁). In addition, adjacent ones of the even word linephoto-mask patterns 204 w and adjacent ones of the even word linephotoresist patterns 158 w may define a period P₁, and the period P₁ maybe about 4 times the width F₁. The width F₁ may be a minimum featuresize available from the photolithography technology being used. Adjacentground select line photo-mask patterns 204 g, adjacent string selectline photo-mask patterns 204 s, adjacent ground select line photoresistpatterns 158 g, and adjacent string select line photoresist patterns 158s may be separated by a width/spacing W₂, and the width/spacing W₂ maybe greater than three times the width F₁. For example, the secondspacing W₂ may be between about 3 and 4 times greater than the firstspacing W₁, or the second spacing W₂ may be more than 3 times greaterthan the first spacing W₁, and still more particularly, more than 4times greater than the first spacing W₁.

More particularly, a continuous photoresist layer may be selectivelyexposed to radiation through the photomask 200 and then developed toprovide the photoresist pattern 158 of FIG. 6A. Accordingly, anarrangement of the photoresist pattern 158 is defined by an arrangementof the photo-mask pattern 204. In addition, the photoresist pattern 158corresponds to a pattern of gate select lines, string select lines, andeven word lines discussed above with respect to FIGS. 3A-B.

Portions of the first hard mask layer 155 (including silicon nitridelayer 156 and pad oxide layer 154) exposed by the photoresist pattern158 may be selectively removed (for example, using dry etching) toprovide a first hard mask pattern 160 (including ground select line hardmask patterns 160 g, string select line hard mask patterns 160 s, dummyword line hard mask pattern 160 d, and even word line hard mask patterns160 w) as shown in FIG. 6B. If the first hard mask layer 155 includesseparate layers 154 and 156, each element of the first hard mask pattern160 may also include separate layers 154 and 156. About a samespacing/width W₁₁ may be provided between a dummy word line hard maskpattern 160 d and a first even word line hard mask pattern 160 w, andbetween adjacent even word line hard mask patterns 160 w. About the samespacing/width W₃ may be provided between a ground select line hard maskpattern 160 g and a dummy word line hard mask pattern 160 d, and betweena last even word line hard mask pattern 160 w and a string select linehard mask pattern 160 s. Each element of the first hard mask pattern 160may include a layer of silicon nitride and/or silicon oxide. Afterselectively removing portions of the first hard mask layer, thephotoresist pattern 158 may be removed.

As further shown in FIG. 6B, a sacrificial mask layer 162 may be formedon the first hard mask pattern 160 and on portions of the etch targetlayer 152 exposed by the first hard mask pattern 160, and thesacrificial mask layer 162 and the first hard mask pattern 160 maycomprise different materials. For example, upper layers 156 of the firsthard mask pattern 160 may be a layer of silicon nitride, and thesacrificial mask layer 162 may be a layer of polysilicon. Moreover, athickness of the sacrificial mask layer 162 may be provided so that:gaps remain between portions of the sacrificial mask layer 162 onsidewalls of adjacent ones of the even word line hard mask patterns 160w; gaps remain between portions of the sacrificial mask layer 162 onsidewalls of adjacent ground select line hard mask patterns 160 g; gapsremain between portions of the sacrificial mask layer 162 on sidewallsof adjacent string select line hard mask patterns 160 s; and gaps remainbetween portions of the sacrificial mask layer 162 on sidewalls ofadjacent dummy word line hard mask patterns 160 d and first even wordline hard mask patterns 160 w. The sacrificial mask layer 162, however,may fill gaps between ground select line hard mask patterns 160 g anddummy word line hard mask patterns 160 c 1, and the sacrificial layer162 may fill gaps between a last of the even word line hard mask pattern160 w and adjacent string select line hard mask pattern 160 s.

A thickness of the sacrificial mask layer 162 on sidewalls of the firsthard mask patterns 160 d, 160 w, 160 g, and 160 s may be about the sameas the width/spacing W₁ between adjacent word lines WL_(x) and WL_(x+1)shown in FIGS. 3A-B. A width/spacing of a gap remaining between portionsof the sacrificial mask layer 162 on adjacent even word line maskpatterns 160 w may be about the same as a width F₁ of an odd word lineWL₁, WL₃, . . . WL_(2n−1) shown in FIGS. 3A-B.

After forming the sacrificial mask layer 162, a second hard mask layer164 may be formed on the sacrificial mask layer 162, as further shown inFIG. 6B. Moreover, the second hard mask layer 164 may be a layer ofsilicon oxide, and the second hard mask layer 164 may have a thicknessthat is at least one half of the width F₁ to thereby fill gaps in thesacrificial mask layer 162 between odd word line hard mask patterns 160w. Because wider gaps are provided between adjacent ground select linehard mask patterns 160 g and between adjacent string select line hardmask patterns 160 s, however, gaps 168 may remain in the second hardmask layer 164. If a thickness of the second hard mask layer 164 isabout the width F₁ of a word line, adjacent ground select line patterns160 g and adjacent string select line patterns 160 s may be separated bya width/spacing greater than four times F₁.

The second hard mask layer 164 may then be subjected to an etch backoperation to remove portions of the hard mask layer 164 from betweenadjacent ground select line hard mask patterns 160 g, from betweenadjacent string select line hard mask patterns 160 s, and from uppersurfaces of the sacrificial mask layer 162, as shown in FIG. 6C.Portions of the second hard mask layer 164 remaining after the etch backoperation may thus have about the thickness F₁. More particularly,portions of the second hard mask layer 164 remaining after the etch backoperation may define a second hard mask pattern 170 on the sacrificialmask layer 162. The second hard mask pattern 170 may include odd wordline patterns 170 w between adjacent even word line patterns 160 w andbetween the last odd word line pattern 160 w and the string select linepattern 160 s.

Exposed portions of the sacrificial mask layer 162 may then be removed(for example, using a dry etch) as shown in FIG. 6D to expose portionsof the etch target layer 152 not covered by the first and/or second hardmask patterns 160 and/or 170. Exposed portions of the etch target layer152 may then be removed (for example, using a dry etch) using the firstand second hard mask patterns 160 and 170 as an etch mask, and the firstand second hard mask patterns 160 and 170 may then be removed to providethe structure of FIGS. 3A-B.

FIG. 4A is a plan view of a non-volatile memory device 40 (such as aflash memory device) according to some embodiments of the presentinvention, and FIG. 4B is a cross-sectional view taken along sectionline IV-IV′ of FIG. 4A. The flash memory device 40 may include aplurality of parallel active regions ACT in a semiconductor substrateSUB separated by device isolation layers. In addition, ground selectlines GSL₀₋₂, string select lines SSL₀₋₂, and memory cell word linesWL_(1-2n) (where n is an integer) may cross the active regions ACT. Moreparticularly, a respective charge storage gate may be provided betweeneach memory cell word line WL_(1-2n) and each active region ACT toprovide a respective memory cell at each intersection of a memory cellword line WL_(1-2n) and an active region ACT. The structure of FIGS.4A-B is similar to that of FIGS. 2A-B with the omission of dummy wordlines.

An even number of memory cell word lines WL_(1-2n) along an activeregion ACT between a ground select line GSL and a string select line SSL(e.g., between GSL₁ and SSL₁) may define a memory cell string includingan even number of memory cells. As further shown in FIGS. 4A-B, adjacentmemory cell strings may be separated by two ground select lines GSL(e.g., GSL₀ and GSL₁) or by two string select lines SSL (e.g., SSL₁ andSSL₂). More particularly, 2^(k) (where k is a positive integer) memorycell word lines WL_(1-2n) may define a memory cell string including2^(k) memory cells used to store data.

Moreover, an order of memory cell word lines WL_(1-2n) of adjacentmemory cell strings may have a mirror image symmetry. For example, anorder of memory cell word lines WL_(1-2n) between ground select lineGSL₀ and string select line SSL₀ may have mirror image symmetry relativeto an order of memory cell word lines WL_(1-2n) between ground selectline GSL₁ and string select line SSL₁. Similarly, an order of memorycell word lines WL_(1-2n) between ground select line GSL₁ and stringselect line SSL₁ may have mirror image symmetry relative to an order ofmemory cell word lines WL_(1-2n) between ground select line GSL₂ andstring select line SSL₂. By providing a sufficient spacing/width WL₄between a ground select line GSL and a first memory cell word line WL₁of a memory cell string, a ground induced leakage current and/or anerase disturbance at the first memory cell word line WL₁ may be reduced.

A controller of the non-volatile memory device may be coupled to theground select lines, the string select lines, and the memory cell wordlines. During an erase operation, for example, the controller may beconfigured to allow the ground select line GSL₁ to float, to apply anerase voltage Vers of about 20 volts to a p-well of the substrate SUB,and to apply 0 volts to the memory cell word lines WL_(1-2n). During awrite (or program) operation, the controller may be configured to applythe supply voltage Vcc to the ground select line GSL₁, to apply 0 voltsto a p-well of the substrate SUB, to apply a pass voltage Vpass to thenon-selected word lines, and to apply a program voltage Vpgm to theselected word line.

As shown in FIGS. 4A-B, each of the memory cell word lines WL₁ toWL_(2n) may have about a same width F₁, and a width/spacing W₅ mayseparate a gate selection line GSL and an adjacent first memory cellword line WL₁ of an associated memory cell string. About the samewidth/spacing W₁ may separate adjacent memory cell word lines WL_(x) andWL_(x+1), and about the same width/spacing W₁ may separate a last memorycell word line WL_(2n) and an adjacent string select line SSL. Moreover,the widths F₁ and W₁ may be about the same, and more particularly, eachof the widths F₁ and W₁ may be about one fourth (¼) of a period P₁defined by adjacent even memory cell word lines WL_(even) andWL_(even+2) (i.e., even memory cell word lines separated by only one oddmemory cell word line), or defined by adjacent odd memory cell wordlines WL_(odd) and WL_(odd+2) (i.e., odd memory cell word linesseparated by only one even memory cell word line). As further shown inFIGS. 4A-B, adjacent ground selection lines GSL₀ and GSL₁ may beseparated by about a width/spacing W₂, and adjacent string selectionlines SSL₀ and SSL₁ may be separated by about the same width/spacing W₂.The spacing/width W₂ may be at least about 3 times greater than thespacing/width W₁. Moreover, the spacing/width W₅ may be greater thanabout three times the spacing/width W₁ (i.e., W₅>3×W₁). For example, thesecond and/or fifth spacings W₂ and/or W₅ may be between about 3 and 4times greater than the first spacing W₁, or the second and/or fifthspacing W₂ and/or W₅ may be more than 3 times greater than the firstspacing W₁, and still more particularly, more than 4 times greater thanthe first spacing W₁.

Each memory cell word line WL₁ to WL_(2n) may thus provide a respectivecontrol electrode for a non-volatile memory cell (such as a flash memorycell) of a memory cell string on a same active region ACT between aground select line (e.g., GSL₁) and a string select line (e.g., SSL₁).Each non-volatile memory cell may also include a charge storage layerbetween the respective memory cell word line and active region, a tunnelinsulating layer between the active region and the charge storage layer,and a barrier insulating layer between the memory cell word line and thecharge storage layer.

The pattern of ground select lines GSL, memory cell word lines WL₁ toWL_(2n), and string select lines SSL may be formed using self-aligneddouble patterning as discussed in greater detail below. For example, theground select lines GSL, the string select lines SSL, and the odd memorycell word lines (WL₁, WL₃, WL₅ . . . WL_(2n−1)) may be formedcorresponding to a pattern of a photolithography mask, and even memorycell word lines (WL₂, WL₄, WL₆ . . . WL_(2n)) may be formed usingself-aligned double patterning.

According to some embodiments of the present invention illustrated inFIGS. 4A-B, a first memory cell string on the active region ACT mayinclude a first plurality of memory cell word lines WL₁ to WL_(2n)crossing the active region ACT between the first ground select line GSL₁and the first string select line SSL₁, and about a same first spacing W₁may be provided between adjacent ones of the first plurality of wordlines. In addition, a second memory cell string on the active region ACTmay include a second plurality of word lines WL₁ to WL_(2n) crossing theactive region ACT between a second ground select line GSL₀ and a secondstring select line SSL₀, and about the same first spacing W₁ may beprovided between adjacent ones of the second plurality of word lines.More particularly, the first ground select line GSL₁ may be between thesecond ground select line GSL₀ and the first plurality of word lines,and the second ground select line GSL₀ may be between the first groundselect line GSL₁ and the second plurality of word lines. Moreover,portions of the active region ACT between the first and second groundselect lines GSL₁ and GSL₀ may be free of word lines, and the secondspacing W₂ between the first and second ground select lines GSL₁ andGSL₀ may be at least about 3 times greater than the first spacing W₁.For example, the second spacing W₂ may be between about 3 and 4 timesgreater than the first spacing W₁, and more particularly, the secondspacing W₂ may be about 3 times greater than the first spacing W₁.

As further shown in FIGS. 4A-B, the first plurality of word lines WL₁ toWL_(2n) may include an even number of memory cell word lines, and aspacing/width W₅ greater than 3 times the first spacing W₁ may beprovided between the ground select line GSL₁ and the first memory cellword line WL₁ of the respective memory cell string. Moreover, about thefirst spacing/width WL₁ may be provided between the last memory cellword line WL_(2n) of the respective memory cell string and the stringselect line SSL₁, and portions of the active region ACT between theground select line GSL₁ and the first memory cell word line WL₁ may befree of word lines.

FIGS. 7A-D are cross-sectional views illustrating operations of formingthe non-volatile memory structures of FIGS. 4A-B using self-aligneddouble patterning according to some embodiments of the presentinvention. As shown in FIG. 7A, a substrate 350 may include an etchtarget layer 352 thereon, and the etch target layer 352 may includelayers of materials used to form the memory cells, word lines, selectiontransistors, and selection lines of FIGS. 4A-B.

More particularly, the target layer may include a tunnel insulatinglayer (such as a layer of silicon oxide), a charge storage gate layer(such as a layer of polysilicon or silicon nitride), a barrierinsulating layer (such as a layer of silicon oxide or other dielectricmaterial different than the charge storage gate layer), and conductivelayer (such as a layer of polysilicon and/or metal). The charge storagelayer may be between the conductive layer and the substrate with thetunnel insulating layer separating the charge storage layer and thesubstrate and with the barrier insulating layer separating the chargestorage layer and the conductive layer. In addition, a first hard masklayer 355 may be formed on the etch target layer 352, and the first hardmask layer 355 may include a silicon nitride layer 356 on a pad oxidelayer 354.

A photoresist layer on the first hard mask layer 355 may be patternedusing the photo-mask 300 to provide the photoresist pattern 358including odd word line photoresist patterns 358 w, ground select linephotoresist patterns 358 g, and string select line photoresist patterns358 s. More particularly, the photo-mask 300 may include a photo-maskpattern 304 on a transparent substrate 302. The photo-mask pattern 304may include odd word line photo-mask patterns 304 w corresponding to oddword line photoresist patterns 358 w, ground select line photo-maskpatterns 304 g corresponding to ground select line photoresist patterns358 g, and string select line photo-mask patterns 304 s corresponding tostring select line photoresist patterns 358 s.

As further shown in FIG. 7A, adjacent odd word line photo-mask patterns304 w may be spaced apart by about a width/spacing W₁₁, and adjacent oddword line photoresist patterns 358 w may be spaced apart by about thewidth/spacing W₁₁. A first of the odd word line photo-mask patterns 304w may be spaced apart from an adjacent ground select line photo-maskpattern 304 g by about a width/spacing W₅, and a last of the odd wordline photo-mask patterns 304 w may be spaced apart from an adjacentstring select line photo-mask pattern 304 s by about the width/spacingW₁₁. Similarly, a first of the odd word line photoresist patterns 358 wmay be spaced apart from an adjacent ground select line photoresistpattern 358 g by about the width/spacing W₅, and a last of the odd wordline photo-mask patterns 358 w may be spaced apart from an adjacentstring select line photo-mask pattern 358 s by about the width/spacingW₁₁.

Moreover, each of the odd word line photo-mask patterns 304 w and eachof the odd word line photoresist patterns 358 w may have a width ofabout F₁, and the width/spacing W₁₁ may be about three times the widthF₁. In addition, adjacent ones of the odd word line photo-mask patterns304 w and adjacent ones of the odd word line photoresist patterns 358 wmay define a period P₁, and the period P₁ may be about 4 times the widthF₁. The width F₁ may be a minimum feature size available from thephotolithography technology being used. Adjacent ground select linephoto-mask patterns 304 g, adjacent string select line photo-maskpatterns 304 s, adjacent ground select line photoresist patterns 358 g,and adjacent string select line photoresist patterns 358 s may beseparated by a width/spacing W₂, and the width/spacing W₂ may be greaterthan three times the width F₁. For example, the second spacing W₂ may bebetween about 3 and 4 times greater than the first spacing W₁, or thesecond spacing W₂ may be more than 3 times greater than the firstspacing W₁, and still more particularly, more than 4 times greater thanthe first spacing W₁.

In addition, a spacing/width W₅ between a first odd word line photo-maskpattern 304 w and an adjacent ground select line photo-mask pattern 304g and between a first odd word line photoresist pattern 358 w and anadjacent ground select line photoresist pattern 358 g may be greaterthan W₁₁ (e.g., greater than three times the width F₁). For example, thespacing/width W₅ may be greater than four times F₁.

More particularly, a continuous photoresist layer may be selectivelyexposed to radiation through the photomask 300 and then developed toprovide the photoresist pattern 358 of FIG. 7A. Accordingly, anarrangement of the photoresist pattern 358 is defined by an arrangementof the photo-mask pattern 304. In addition, the photoresist pattern 358corresponds to a pattern of gate select lines, string select lines, andodd word lines discussed above with respect to FIGS. 4A-B.

Portions of the first hard mask layer 355 (including silicon nitridelayer 356 and pad oxide layer 354) exposed by the photoresist pattern358 may be selectively removed (for example, using dry etching) toprovide a first hard mask pattern 360 (including ground select line hardmask patterns 360 g, string select line hard mask patterns 360 s, andodd word line hard mask patterns 360 w) as shown in FIG. 7B. If thefirst hard mask layer 355 includes separate layers 354 and 356, eachelement of the first hard mask pattern 360 may also include separatelayers 354 and 356. About the spacing/width W₅ (greater than W₁₁) may beprovided between a ground select line hard mask pattern 360 g and afirst odd word line hard mask pattern 360 w. About the samespacing/width W₁₁ may be provided between adjacent odd word line hardmask patterns 360 w, and between a last odd word line hard mask pattern360 w and a string select line hard mask pattern 360 s. Each element ofthe first hard mask pattern 360 may include a layer of silicon nitrideand/or silicon oxide. After selectively removing portions of the firsthard mask layer, the photoresist pattern 358 may be removed.

As further shown in FIG. 7B, a sacrificial mask layer 362 may be formedon the first hard mask pattern 360 and on portions of the etch targetlayer 352 exposed by the first hard mask pattern 360, and thesacrificial mask layer 362 and the first hard mask pattern 360 maycomprise different materials. For example, upper layers 356 of the firsthard mask pattern 360 may be a layer of silicon nitride, and thesacrificial mask layer 362 may be a layer of polysilicon. Moreover, athickness of the sacrificial mask layer 362 may be provided so that:gaps remain between portions of the sacrificial mask layer 362 onsidewalls of adjacent ones of the odd word line hard mask patterns 360w; gaps remain between portions of the sacrificial mask layer 362 onsidewalls of adjacent ground select line hard mask patterns 360 g; gapsremain between portions of the sacrificial mask layer 362 on sidewallsof adjacent string select line hard mask patterns 360 s; gaps remainbetween portions of the sacrificial mask layer 362 on sidewalls ofadjacent select line hard mask patterns 360 g and first odd word linehard mask patterns 360 w; and gaps remain between portions of thesacrificial mask layer 362 on sidewalls of adjacent select line hardmask patterns 360 s and last odd word line hard mask patterns 360 w.

A thickness of the sacrificial mask layer 362 on sidewalls of the firsthard mask patterns 360 w, 360 g, and 360 s may be about the same as thewidth/spacing W₁ between adjacent word lines WL_(x) and WL_(x+1) shownin FIGS. 4A-B. A width of a gap remaining between portions of thesacrificial mask layer 362 on adjacent odd word line mask patterns 360Wmay be about the same as a width F₁ of an even word line WL₂, WL₄, . . .WL_(2n) shown in FIGS. 4A-B.

After forming the sacrificial mask layer 362, a second hard mask layer364 may be formed on the sacrificial mask layer 362, as further shown inFIG. 7B. Moreover, the second hard mask layer 364 may be a layer ofsilicon oxide, and the second hard mask layer 364 may have a thicknessthat is at least one half of the width F₁ to thereby fill gaps in thesacrificial mask layer 362 between odd word line hard mask patterns 360w. Because wider gaps are provided between adjacent ground select linehard mask patterns 360 g, between adjacent string select line hard maskpatterns 360 s, and between ground select line hard mask patterns 360 gand adjacent first odd word line hard mask patterns 360 w, however, gaps368 may remain in the second hard mask layer 364. If a thickness of thesecond hard mask layer 364 is about the width F₁ of a word line,adjacent ground select line patterns 360 g, adjacent string select linepatterns 360 s, and ground select line hard mask patterns 360 g andadjacent first odd word line hard mask patterns 360 w may be separatedby a width/spacing greater than four times F₁.

The second hard mask layer 364 may then be subjected to an etch backoperation to remove portions of the hard mask layer 364 from betweenadjacent ground select line hard mask patterns 360 g, from betweenadjacent string select line hard mask patterns 360 s, from betweenground select line hard mask patterns 360 g and adjacent first odd wordline hard mask patterns 360 w, and from upper surfaces of thesacrificial mask layer 362, as shown in FIG. 7C. Portions of the secondhard mask layer 364 remaining after the etch back operation may thushave about the thickness F₁. More particularly, portions of the secondhard mask layer 364 remaining after the etch back operation may define asecond hard mask pattern 370 on the sacrificial mask layer 362. Thesecond hard mask pattern 370 may include even word line patterns 370 wbetween adjacent odd word line patterns 360 w and between the last oddword line patterns 360 w and the adjacent string select line pattern 360s.

Exposed portions of the sacrificial mask layer 362 may then be removed(for example, using a dry etch) as shown in FIG. 7D to expose portionsof the etch target layer 352 not covered by the first and/or second hardmask patterns 360 and/or 370. Exposed portions of the etch target layer352 may then be removed (for example, using a dry etch) using the firstand second hard mask patterns 360 and 370 as an etch mask, and the firstand second hard mask patterns 360 and 370 may then be removed to providethe structure of FIGS. 4A-B.

According to embodiments of the present invention, NAND-type nonvolatilememory devices may be provided having structures with dimensions smallerthan dimensions that may be available using one photolithographicexposure followed by one etch. Accordingly, NAND-type nonvolatile memorydevices having relatively fine line and space patterns (such as patternsof word lines) may be provided, and increased integration density and/orincreased performance may result.

While the present invention has been particularly shown and describedwith reference to embodiments thereof, it will be understood by those ofordinary skill in the art that various changes in form and details maybe made therein without departing from the spirit and scope of thepresent invention as defined by the following claims.

1. A method of forming a non-volatile memory device, the methodcomprising: forming an etch target layer on a substrate; forming firsthard mask patterns including a plurality of odd word line patternsbetween first and second select line patterns, wherein about a samespacing is provided between the first select line pattern and a firstodd word line pattern, between adjacent odd word line patterns, andbetween a last odd word line pattern and the second select line pattern,wherein the first hard mask pattern comprises a first material; forminga sacrificial mask layer on the first hard mask pattern, wherein gapsremain between portions of the sacrificial mask layer on sidewalls ofadjacent ones of the odd word line patterns, wherein the sacrificialmask layer comprises a second material, and wherein the first and secondmaterials have different compositions; forming second hard mask patternson the sacrificial mask layer, wherein the second hard mask patternsincludes a dummy word line pattern between the first select line patternand the first odd word line pattern and includes even word line patternsbetween adjacent odd word line patterns and between the last odd wordline pattern and the second select line pattern, wherein the second hardmask pattern comprises a third material, and wherein the second andthird materials have different compositions; removing portions of thesacrificial mask layer between the first and second hard mask patternsso that portions of the etch target layer are exposed between the firstand second hard mask patterns; and etching portions of the etch targetlayer exposed between the first and second hard mask patterns.
 2. Amethod according to claim 1 wherein the spacing provided between thefirst select line pattern and the first odd word line pattern is aboutthree times a width of the first odd word line pattern.
 3. A methodaccording to claim 1 wherein the first hard mask patterns comprisesilicon nitride, wherein the sacrificial mask layer comprisespolysilicon, and wherein the second hard mask patterns comprise siliconoxide.
 4. A method according to claim 1 wherein the odd word linepatterns have about a same width and wherein the spacing betweenadjacent ones of the plurality of the odd word line patterns is greaterthan the width of the odd word line patterns.
 5. A method according toclaim 1 wherein forming the etch target layer comprises, forming acharge storage layer on the substrate, forming a barrier insulatinglayer on the charge storage layer, and forming a control gate layer onthe barrier insulating layer.
 6. A method of forming a non-volatilememory device, the method comprising: forming an etch target layer on asubstrate; forming first hard mask patterns on the substrate wherein thefirst hard mask patterns include a plurality of even word line patternsbetween first and second select line patterns and a dummy word linepattern between the first select line pattern and a first even word linepattern, wherein about a same first spacing is provided between thedummy word line pattern and the first even word line pattern and betweenadjacent even word line patterns, and wherein a second spacing isprovided between the first select line pattern and the dummy word linepattern and between a last even word line pattern and the second selectline pattern, wherein the second spacing is less than the first spacing,and wherein the first hard mask patterns comprise a first material;forming a sacrificial mask layer on the first hard mask patterns whereingaps remain between portions of the sacrificial mask layer on sidewallsof adjacent ones of the even word line patterns and between the dummyword line pattern and the first even word line pattern, wherein thesacrificial mask layer comprises a second material, and wherein thefirst and second materials have different compositions; forming secondhard mask patterns in the gaps on the sacrificial layer wherein thesecond hard mask patterns comprise odd word-line patterns betweenadjacent even word line patterns and between the dummy word line patternand the first even word line pattern, wherein the second hard maskpatterns comprise a third material, wherein the second and thirdmaterials have different compositions; removing portions of thesacrificial mask layer between the first and second hard mask patternsso that portions of the etch target layer are exposed between the firstand second hard mask patterns, wherein a space between the dummy wordline pattern and the first select line pattern is free of any of thesecond hard mask patterns; and etching portions of the etch target layerexposed between the first and second hard mask patterns.
 7. A methodaccording to claim 6 wherein the first spacing provided between thedummy word line pattern and a first even word line pattern and betweenadjacent even word line patterns is about three times a width of thefirst even word line pattern.
 8. A method according to claim 7 whereinthe second spacing is greater than a width of the first even word linepattern and no greater than two times the width of the first even wordline pattern.
 9. A method according to claim 6 wherein the secondspacing is in the range of about 1.5 times the width of the first evenword line pattern to about 2 times the width of the first even word linepattern.
 10. A method according to claim 6 wherein the even word linepatterns have about a same width and wherein the spacing betweenadjacent ones of the plurality of the even word line patterns is greaterthan the width of the even word line patterns.
 11. A method according toclaim 6 wherein forming the etch target layer comprises, forming acharge storage layer on the substrate, forming a barrier insulatinglayer on the charge storage layer, and forming a control gate layer onthe barrier insulating layer.
 12. A method of forming a non-volatilememory device, the method comprising: forming an etch target layer on asubstrate; forming first hard mask patterns on the substrate, whereinthe first hard mask patterns include a plurality of odd word linepatterns between first and second select line patterns, wherein about asame first spacing is provided between adjacent odd word line patternsand between a last odd word line pattern and the second select linepattern, and wherein a second spacing is provided between the firstselect line pattern and a first odd word line pattern, wherein thesecond spacing is greater than the first spacing, and wherein the firsthard mask patterns comprise a first material; forming a sacrificial masklayer on the first hard mask patterns, wherein gaps remain betweenportions of the sacrificial mask layer on sidewalls of adjacent firsthard mask patterns wherein the sacrificial mask layer comprises a secondmaterial, and wherein the first and second materials have differentcompositions; forming second hard mask patterns on the sacrificial layerwherein the second hard mask patterns include even word line patternsbetween adjacent odd word line patterns and between the last odd wordline pattern and the second select line pattern, wherein a space betweenthe first select line pattern and the first odd word line pattern isfree of any of the second hard mask patterns, wherein the second hardmask patterns comprise a third material, and wherein the second andthird materials have different compositions; removing portions of thesacrificial mask layer between the first and second hard mask patternsso that portions of the etch target layer are exposed between the firstand second hard mask patterns; and etching portions of the etch targetlayer exposed between the first and second hard mask patterns.
 13. Amethod according to claim 12 wherein the same first spacing is aboutthree times a width of the first odd word line pattern.
 14. A methodaccording to claim 12 wherein fondling the etch target layer comprises,forming a charge storage layer on the substrate, forming a barrierinsulating layer on the charge storage layer, and forming a control gatelayer on the barrier insulating layer.